Most artificial vascular grafts, of which 60,000 were implanted in the USA last year, fail in less than three years, leading to amputation. Diminishing blood flow through the graft has been shown to be a precursor of raft failure. The long-term objective of this program is to extend artificial graft life by making the grafts "smart", i.e. making the graft capable of measuring its flow and calling a physician for intervention if the flow diminishes. Phase I of the program achieved its specific aims of 1) demonstrating accurate flow measurement using a Doppler sensor small enough to be completely embedded in a vascular graft and 2) designing circuitry capable of driving the sensor and wirelessly transmitting the flow information to a bedside monitor while consuming low enough power for 5-years of life from an implantable battery. Phase II is to provide data to enable human clinical trials. Component life and reliability will be validated, and functional smart grafts will be fabricated and implantated in animals. Animal trials will demonstrate the safety, functionality, and extended graft life of these devices.